MSA-C vs MSA-P – Subtype Classification — SCE Neurology MCQ

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ModerateMovement DisordersMSA-C vs MSA-P – Subtype ClassificationSCE Neurology

A 65-year-old man with PD has progressive symmetric parkinsonism, cerebellar ataxia, and autonomic failure. His levodopa response is poor. MRI brain shows the 'hot cross bun' sign in the pons and cerebellar atrophy. What MSA subtype does the cerebellar predominance indicate?

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Correct answer: C — MSA-C (cerebellar-predominant)

MSA is classified into two subtypes based on the predominant motor features: MSA-P (parkinsonian-predominant — extrapyramidal features dominate) and MSA-C (cerebellar-predominant — cerebellar ataxia dominates). Both have autonomic failure and poor levodopa response. MRI findings: MSA-P has putaminal rim hyperintensity; MSA-C has hot cross bun sign (cruciform pontine hyperintensity from selective loss of myelinated transverse pontocerebellar fibres) and cerebellar atrophy. A: MSA-P has predominantly parkinsonian features. C: PSP has vertical gaze palsy. D: DLB has visual hallucinations and fluctuating cognition. E: CBD has asymmetric apraxia and cortical sensory loss.

Reference: MDS MSA Diagnostic Criteria (2022); NICE NG71